Drafting or measuring instrument.



J. HERMAN.

DRAFTING OR MEASURING INSTRUMENT.

APPLICATION FILED OCT. 24.1918.

Patented Feb. 11, 1919.

llinil DRAFTING OR MEASURING INSTRUMENT.

Specification of Letters Patent.

Patented Feb. 11, 1919.

Application filed October 24, 1918. Serial No. 259,466.

To all wkomit may concern:

Be it known that I, JOHN HERMAN, a citizen of the United States,residing at Easton, in the county of Northampton and State ofPennsylvania, have invented new and useful Improvements in Drafting orMeasuring Instruments, of which the following 1s a specification.

This invention relates to urlng lnstruments or tools, and has for anobject to provide an improved tool of this character having a plurality.of interchangeable leg extensions whereby said ,tool may I be convertedinto and used as compasses, dividers, callpers, or other instrument ofsimilar type, said leg extensions and the means for attaching the samebeing of such a character that one extension or pair ,of extensions maybe readily substituted for another, and that said extensions will besecurely held in accurate position, these results being accomplished bythe use of parts of relatively simple and inexpensive construction.

Another object of the invention is to provide, in an instrument of'thecharacter referred to, improved and simplified means for connecting andoperating the parts whereby the instrument may be quickly andconveniently adjusted and the parts thereof steadied and securely heldin adjusted position when in use.

' The foregoing and other objects of the invention, together with meanswhereby the same may be carried into effect, will best be understoodfrom the'follo wing description of one form or embodiment thereof illustrated in the accompanying drawings. It will be understood, however,that the pardrafting or meason the lines 3-3, 4-4, and 5 5,respectively, Fig. 1.

Referring to Fig. 1, the instrument comprises a pair of pivotallyconnected leg members 10, a pair of leg extensions 11 carried by saidleg members, and means, hereinafter described, whereby said legmembers'may be relatively adjusted abouttheir pivot and retained inadjusted position.

'As herein shown, the leg members 10 are coaxially pivoted upon oppositesides of a disk or flat cylindrical block12 (Figs. 2 and having opposingprojecting alined trunnlons 13 which are received in openings in thehubs 141.- of said leg members, said hubs being retained in, place bysuitable means, as by riveting or upsetting the outer ends of saidtrunnions to form heads 15. Preferably, and as'shown in Fig. 5, the hubsof the respective leg members 10 are oppositely offset to engageoppositefaces of the block or disk .12 while bringing said leg members intosubstantially the same plane.

Adjacent their outer ends the leg members 10 are formed with sockets 16(see Fig. 4:) and; with openings 17 extending therethrough from thebottoms of the sockets. Loosely received in said sockets are heads 18having threaded stems 19 of less diameter than the openingsl? anddisposed therein,

"said stems being fitted with knurled nuts 20 engaging the oppositefaces of the leg members. The heads 18 are provided with transverseperforations to receive the shanks 21 of the leg extensions.

Said leg extensions may be of any suitable or desired form, andpreferably a plurality of interchangeable sets are provided for eachinstrument. In Fig. 1 is shown a pair of extensions 11 of suitable shapeto adapt the instrument for use as a pair of internal calipers, while inFig. 2 is shown in full lines a .pair of extensions 11 constitutingexternal caliper jaws, and in dotted lines extensions 11 adapted toconvert the instrument into a pairof dividers. Obviously ex tensionscapable of rendering the instrument operative as a pair of draftsmanscompasses or as any other drafting or measuring instrument of similartype might be provided.

' The extreme ends of the shanks 21 are bifurcated, as shown at 22, toengage studs 23 carried by the leg members 10 at points spaced from thesockets 16, whereby, when the shanks are passed throughtheperforationsin the heads 18 and the ends thereof engaged with saidstuds, said shanks will overlap the leg members and will be accuratelypositioned with respect thereto, while by tightening the nuts 20 saidshanks will be securely clamped in position. It will be noted that theloose mounting of the clamping devices 18, 19in the sockets 16, andparticularly the looseness of the stems 19 in the openings 17 permitssaid clamping devices to adjust themselves to the reoluirements, sothat. any variations in workmanship in the several leg extensions of theset is automatically compensated for. It

a will also be observed that the leg extensions may be easily andquickly attached, re-

moved, or interchanged merely by tightening or loosening the nuts 20 andslipping the shanks 21 "into or out of the perforations in the heads 18,the engagement of the bifurcated ends ofsaid shanks serving auto-'matically to effect the longitudinal as well as the angular positioningof the leg extensions without special attention on the part of the user,so that a change may be made in a minimum length of time and with aminimum amount of trouble or possibility of error.

The disk or block 12 is formed with 2. diametrically disposed threadedopening to receive an adjusting screw24 provided at its outer end with asuitable operating lmob or handle 25. At its inner endthe screw 24 isswiveled in a second disk or block 26 having alined trunnions 27 similarto the trunnions13, and upon which are pivoted the inner ends of togglelinks 28 pivoted at their outer ends to the leg members 10. Preferably,and as herein shown, a pair of links 28 is employed to connect the block26 with each of the leg members, the links of each pair being spacedfrom one another and pivoted respectively to opposite sides of the legmembers and of the block, one link of each pair being mounted on one ofthe trunnions 27. The construction shown affords a. very simple,inexpensive, and easily operated means whereby the leg members outfurther description.

For the purpose of steadying the leg members in their adjusted positionsthere is provided a bow spring 29 which surrounds and incloses the block26, extends between the links 28 of each pair, and is engaged at itsends in sockets 30 in the inner sides of the leg members 10, said springserving in a measure to protect and house the adjusting mechanism, andbeing itself protected against accidental dislodgment by the links 28.

As will be seen the invention provides a very simple, inexpensive, andconveniently operated instrument of the character de scribed, whereinthe necessity for extremely fine and accurate workmanship inmanufacture, is obviated, which nevertheless is reliable and accurate inuse, which by a quick and simple manipulation can be adapted to avariety of purposes, and which possesses many other advantages whichwill be readily recognized by those skilled in the art. i r

I claim: 7

1. In an instrument of the character. .de-

cooperating positioning means on said leg member and leg extension atthe inner end of the latter.

2. In an instrument of the character deand engaged by said clampingmeans, and

scribed, incombination, a leg member, a leg 7 extension carried by andoverlapping said leg member, said leg extension having a bifurcatedinner end, meansfor clamping said extension to said member, and a studon said member engaged by the'bifurcated end of said extension.

3; In an instrument of the character described, incom bination, a legmember having a socket and an opening extending therethrough from thebottom of said socket, a perforated headloosely received in said socketand having a threaded stem ofless' diameter than said opening disposedtherein, a nut on said threaded stem beyond said leg extensions eachhaving ashank adapted to be received in the perforation of said head,and cooperating positioning means on said leg member and shanks.

member, a plurality of interchangeable leg 4. In an instrument of thecharacter de- I scribed, in combination, a pair of pivotally connectedleg members each having adjacent its outer end a socket and an openinextending therethrough from the bottom 0 said socket, a perforated headloosely re:

ceived in each of said sockets'and having a threaded stem of lessdiameter than the corresponding opening disposed therein, nuts on saidstems beyond said leg members, a

plurality of pairs of interchangeable leg extensions each having a shankadapted to be received in the perforations in said heads, said shankshaving bifurcated inner ends, and studs on said leg members spaced fromsaid sockets and engaged by the bifurcated end of said shanks when saidleg extensions are in position.

5. In an instrument of the character dearound said second block andbetween the scribed, in combination, a block, a pair of links of eachpair, said spring engaging at leg members pivoted to said block, asecond its ends said leg members to steady the same. block, an adjustingscrew sWiveled in one In testimony whereof I have hereunto set of saidblocks and in threaded engagement my hand in presence of two subscribing15 With the other, a pair of links connecting Witnesses.

said second block With each of said leg JOHN HERMAN. members, the linksof each pair being piv- WVitnesses: oted, respectively, to oppositesides of said GEO. W. BARNET,

'2 second block, and a boW spring extending T. LYNN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner ti Patentl, Washington, D. 0.

